1. Field of the Invention
The present invention relates to an opening and closing motion control device which is constructed so as to perform an opening and closing motion of a closing member, such as a door window of a vehicle, by using a driving unit, for exempt, a motor for driving the door window. Particularly, it relates to an opening and closing motion control device which is capable of avoiding the closing member""s pinching an object, which may be caused with respect to the closing motion of the member, with a simple and cheap arrangement and high accuracy, irrespective of conditions of the object.
2. Description of the Related Art
Hitherto, there is generally known an opening and closing motion control device which is constructed so as to perform the opening and closing motion of the closing member, for example, the door window for the vehicle, a roof window thereof, etc. by using the motor or the like.
As one example of the opening and closing motion control devices of this kind, Japanese Unexamined Patent Publication No. 62-68,118 discloses a power window driving device apparatus which can avoid the closing member""s pinching of the object, which pinching may be caused in the closing motion of the closing member.
The power window driving device includes a sensing part of an electrostatic-capacity type of proximity switch positioned on an upper end of a window frame and a limit switch arranged in a position before the proximity switch""s detection of the door window and also activated by the rising of the door window. In the rising operation of the door window, when the limit switch is inactivated, the power window driving device is constructed so as to stop the operation or lower the door window by a detection output of the proximity switch. While, in the rising operation of the door window, when the limit switch is activated, the power window driving device is constructed so as to stop the, function of the proximity switch.
According to the art disclosed in the above publication, when there is an object (e.g. a hand, fingers, etc.) in the vicinity of the window frame where the sensing part of the proximity switch is positioned, then the sensing part of the proximity switch detects the presence of the object thereby to stop or lower the door window automatically. In this way, the object can be prevented from being pinched by the door window.
However, the above-mentioned power window driving device have problems to be solved, as follows. That is, since the pinching of the object is detected by using the electrostatic-capacity type of proximity switch, there is a need to provide the above-mentioned limit switch specially, causing the manufacturing cost to be increased by the complicated circuits in the device. In addition, there is a possibility that the detection of pinching cannot be maintained with high accuracy.
We now describe the reason why it is necessary to provide the limit switch specially. First, it should be noted that the electrostatic-capacity type of proximity switch usually detects an airborne capacity corresponding to the surrounding atmosphere, such as the ground, the window frame, etc. even when no object exists in the surroundings. Therefore, providing that no limit switch is provided in the device, in even a case of closing the door window without pinching the object, the electrostatic-capacity type of proximity switch will regard the approaching door window as the object by mistake, so that the door window will be stopped or lowered. This is the reason why it is necessary to provide the limit switch specially.
On the other hand, the possibility that the detection of pinching cannot be maintained with high accuracy comes from the following situation. Note again, the electrostatic-capacity type of proximity switch detects whether the object is approaching, by detecting a change in electrostatic-capacity. Therefore, if the dressed passenger""s hand or fingers are pinched between the window frame and the door window door, there is a case that the proximity switch cannot detect the pinching.
Under such a situation, the persons in this art have looked forward to the development of new technique by which it is possible to avoid pinching of the object irrespective of conditions thereof, with the simple and cheap constitution and high accuracy.
It is therefore an object of the present invention to provide a simple and cheap opening and closing motion control device which is capable of avoiding the pinching of the object, which pinching may be caused with the closing motion of a closing member, irrespective of conditions of the object, with high accuracy.
The above-mentioned object can be solved by providing an opening and closing motion control device which is constructed so as to perform an opening and closing motion of a closing member by using a driving unit for driving the closing member, the opening and closing motion control device comprising:
a flexible seal member arranged along a contact portion of a ground potential member, the contact portion being touched by the closing member when the closing member is closed up perfectly;
a linear electrostatic-capacity detecting unit embedded in the seal member, for always detecting an electrostatic capacity in the circumference of the electrostatic capacity detecting unit and also outputting the so-obtained electrostatic capacity;
a pinching judging unit electrically connected to the electrostatic-capacity detecting unit, for judging whether or not an object is pinched by the closing motion of the closing member, on the basis of the detection of pinching by the electrostatic capacity detecting unit; and
a drive control unit electrically connected to the pinching judging unit, allowing the driving unit to either stop the closing member or start the opening motion of the closing member when the pinching judging unit judges that the object is on the point of being pinched.
In operation of the above-constructed opening and closing motion control device, the linear electrostatic-capacity detecting unit embedded in the seal member always detects the electrostatic capacity in the circumference. Then, upon receipt of an output from the linear electrostatic-capacity detecting unit, the pinching judging unit judges whether or not the object is pinched by the closing motion of the closing member.
Regarding the principles of judgement in the pinching judging unit, when the object is pinched between the closing member and the ground potential member, then the object is firstly pressed on the seal member due to the closing motion of the closing member, so that the flexible seal member deforms its own profile corresponding to a pressure applied thereon. At this time, a distance between the liner electrostatic-capacity detecting unit and the ground potential member is shortened in comparison with that in the normal state where no pinching of the object is caused. As the result, the detection output of the electrostatic-capacity detecting unit changes from the detection output in the normal state. Upon detection of this sequential change in electrostatic capacity, the pinching judging unit judges that the object is pinched between the closing member and the ground potential member.
On the other hand, when the pinching of the object is judged by the pinching judging unit, the drive control unit makes the driving unit to either stop or open the closing member in order to prevent the object from being pinched.
Here, we compare the afore-mentioned prior art with the present invention.
Since it is judged by using the electrostatic-capacity proximity switch whether or not the object is approaching in the prior art, there is a possibility of regarding the approaching window glass as the object by mistake, which requires to provide the special limit switch in view of eliminating the erroneous detection. On the contrary, according to the invention, it is regarded as the pinching of the object when it is on the point of being pinched. Therefore, there is no need to provide the above limit switch, providing a simple and low-priced structure of the device.
Again in the prior art, when the dressed passenger""s fingers or hand is pinched between the window frame and the window glass, there is a case that the pinching cannot be detected. On the contrary, according to the invention, it is regarded as the pinching of the object when it is on the point of being pinched. Thus, it is possible, to avoid the pinching of the object irrespective of its conditions, with high accuracy.
In summary, according to the above-mentioned opening and closing control device, it is possible to avoid the pinching of the object, which may be caused with the closing of the closing member, irrespective of the conditions, with high accuracy and also the simple and low-priced structure.
According to the second aspect of the invention, in the above-mentioned opening and closing motion control device, the electrostatic-capacity detecting unit is embedded in the seal member at a designated distance from the contact portion of the ground potential member, the contact portion being touched by the closing member when the closing member is closed up perfectly.
Then, with the arrangement of the electrostatic-capacity detecting unit, when it is promoted to mass-produce the opening and closing motion control devices, the distance between the liner electrostatic-capacity detecting unit and the ground potential member can be uniformly managed through respective production lots. Consequently, the preliminary work through the respective production lots, such as a gain adjustment, becomes useless, providing the opening and closing Motion control devices suitable for the mass-production.
According to the third aspect of the invention, in the above-mentioned opening and closing motion control device, the closing member is identical to a glass which is provided on an opening of a vehicle, while the seal member is identical to a weather strip which is provided along the contact portion of the ground potential member, the contact portion being touched by the closing member when the closing member is closed up perfectly.
With the adoption of the glass and the weather strip, it is possible to apply the present opening and closing motion control device to a power window driving device, a sun roof driving device and so on, properly.
According to the fourth aspect of the invention, the above-mentioned opening and closing motion control device further comprises an oscillating unit electrically connected to the electrostatic-capacity detecting unit, for oscillating a frequency signal corresponding to a detection output from the electrostatic-capacity detecting unit; a converting unit electrically connected to the oscillating unit, for converting the frequency signal outputted by the oscillating unit into an alternating voltage and also outputting an alternating voltage signal derived from the alternating voltage, and an amplification unit electrically connected to the converting unit, for amplifying the alternating voltage signal converted by the converting unit at a predetermined amplifying ratio. In this device, the pinching judging unit judges whether or not the object is pinched by the closing motion of the closing member, on the basis of the alternating voltage signal amplified by the amplification unit.
According to the fifth aspect of the invention, preferably, the opening and closing motion control device of the fourth aspect further comprises a detection unit electrically connected to the converting unit, for picking up a signal related to the sequential change in electrostatic-capacity from the alternating voltage signal and outputting the signal to the amplification unit.
Note, if merely converting the frequency signal outputted from the oscillating unit into a direct voltage and if there is produced an offset in detection output under the influence of disturbance, there would be a possibility of erroneous judgement where it is regarded as the pinching of the object although it is not pinched in reality. On the contrary, according to the fourth and fifth aspects of the invention, even if there is produced an offset in detection output under the influence of disturbance (e.g. adhering of dusts, rain, snow, etc.), it is possible to surely avoid the pinching of the object without being influenced by the disturbance since the present device is capable of detecting the change in electrostatic capacity standardizing the condition including the influence of disturbance, with ease.
According to the sixth aspect of the invention, preferably, the opening and closing motion control device of the fourth aspect further comprises an A/D (analog/digital) converting unit electrically connected to the amplification unit, for converting the alternating voltage signal amplified by the amplification unit to a digital signal, and a calculating unit electrically connected to the A/D converting unit, for calculating a voltage build-up rate by analyzing the digital signal converted by the A/D converting unit by time. In this device, the pinching judging unit judges whether or not the object is pinched by the closing motion of the closing member, on the basis of the voltage build-up rate calculated by the calculating unit.
Accordingly, even if it is hard to obtain a sufficient sequential change in electrostatic capacity due to the disturbance factor, such as contour of the contact portion of the ground potential member, it is possible to judge whether or not the object is pinched by the closing motion of the closing member with reference to the voltage build-up rate allowing even a tiny change in electrostatic capacity to be captured with ease, relatively. As the result, it is possible to avoid the pinching of the object irrespective of its conditions, with high accuracy.
According to the seventh aspect of the present invention, there is also provided an opening and closing motion control device which is constructed so as to perform an opening and closing motion of a closing member by using a driving unit for driving the closing member, the opening and closing motion control device comprising:
at least one plane seal member arranged along a contact portion of a non-conductive member, the contact portion being touched by the closing member when the closing member is closed up perfectly, the plane seal member having both flexibility and electrical insulation;
at least one plane electrostatic-capacity detecting unit laminated on the plane seal member, for always detecting an electrostatic capacity in the circumference of the electrostatic capacity detecting unit and also outputting the so-obtained electrostatic capacity;
a pinching judging unit electrically connected to the electrostatic-capacity detecting unit, for judging whether dr not an object is pinched by the closing motion of the closing member, on the basis of the detection of pinching by the plural electrostatic-capacity detecting unit; and
a drive control unit electrically connected to the pinching judging unit, allowing the driving unit to either stop the closing member or start the opening motion of the closing member when the pinching judging unit judges that the object is on the point of beings pinched.
In addition to the operation of the former opening and closing motion control device, since the electrostatic-capacity detecting unit and the seal member is laminated on each other, even if the member to be touched by the closing member in case of closing it perfectly is non-conductive, it is possible to obtain the opening and closing motion control device which is superior in terms of the effect of increasing the change in electrostatic-capacity and the effect of avoiding the influence of disturbance.
According to the eighth aspect of the invention, in the device of the seventh aspect, the plural plane seal members and the plural plane electrostatic-capacity detecting units are laminated by turns.
In this case, since the electrostatic-capacity detecting units (layers) and the seal members (electrical insulation layers) are arranged in a multi-layer structure, even if the ground potential material is non-conductive, it is possible to obtain the opening and closing motion control device which is more superior in terms of the effect of increasing the change in electrostatic-capacity and the effect of avoiding the influence of disturbance, in comparison with the device of the seventh aspect.
These and other objects and features of the present invention will become more fully apparent from the following description and appended claims taken in conjunction with the accompany drawing.